Applied cargo clippy fixes to clean up codebase:
- Removed unused imports (serde_json::json, std::collections::HashSet)
- Removed unused function encode_hex_for_log
- Modernized format strings to use inline variables
- Fixed clippy warnings for better code quality
All changes applied automatically by cargo clippy --fix
- Add UiButtonContext component for context menu support on buttons
- Implement vault trash functionality using trash crate
- Move vaults to system trash on desktop (with fallback to permanent delete on mobile)
- Add context menu to vault list items for better mobile UX
- Keep hover delete button for desktop users
